Yarn package support inspector



Nov. 18, 1969 J. A. MASINO ET AL YARN PACKAGE SUPPORT INSPECTOR Filed Oct. 18, 1967 2 Sheets-Sheet 1 FIG.!

INVENTORS J. STURDEVANT JOHN ALBERT IASINO EUGENE STANLEY VICTOR WILLIAMS ATTORNEY NOV. 18, J A MASlNo ET AL YARN PACKAGE SUPPORT INSPECTOR 2 Sheets-Sheet 2 Filed Oct. 18. 1967 FIG.4

IEIORY m3 DISORIHINATOR INTERROGATOR IN VENTORS JOHN ALBERT MASINO EUGENE J. STURDEVANT STANLEY VICTOR WILLIAMS ATTORNEY United States Patent ,479,520 YARN PACKAGE SUPPORT INSPECTOR John Albert Masino, Eugene J. Sturdevant, and Stanley Victor Williams, Wilmington, Del., assignors to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware Filed Oct. 18, 1967, Ser. No. 676,158 Int. Cl. G01n 21/48, 21/32 US. Cl. 250-222 2 Claims ABSTRACT OF THE DISCLOSURE A process and apparatus for simultaneously detecting defects on adjacent areas of contiguous end and peripheral surfaces of a rotating opaque cylinder wherein a beam of light is directed substantially tangent to a point at which the surfaces meet. The reflected light in a nonspecular plane common to both surfaces is monitored by photosensitive means which is able to simultaneously detect defects in the illuminated areas of both surfaces through variations in the intensity of the reflected light.

Background of the invention This invention relates generally to objective inspection of Opaque cylindrical objects and more specifically to a photoelectric device to detect and measure nicks, depressions, or protrusions on the end of a cylindrical yarn package support and signal occurrences of defects having unacceptably high magnitude.

When yarn is taken from a package for further processing or use, it is customary to pull the yarn off over one end of the package support (hereinafter called core) without rotating the package. If defects, such as nicks, dents, or protrusions are present on the end of the core, the yarn may be snagged and the yarn removal process disrupted or broken filaments produced. Core end inspection has in the past generally been done subjectively by eye or feel. This method is time-consuming, costly and subject to human error of judgment. Apparatus is known which detects defects on bobbins that might cause snagging. For example, British Patent No. 1,042,367 teaches the use of a fabric covered detector head supported on a transducer and arranged so that, as the detector is moved in contact with the bobbin, any snagging produces an electric signal. This device is complex and difficult to apply to the limited free core end on a full yarn package in such a way as to detect snagging in an axial direction. Furthermore, it would require physical contact with the core. Ability to inspect the free end of a core while it is carrying a full yarn package is required so that inspection can be made after winding and just prior to releasing the package for shipment. It is also important to minimize physical contact with the package and core in order to reduce the possibility of damaging the yarn or the core.

Summary of the invention In accordance with the invention, a light source is directed substantially tangent to a point where the annular end and peripheral surfaces of the exposed section of a yarn package support meet to simultaneously illuminate adjacent areas of the surfaces. The intensity of the re flections from the illuminated areas of the surfaces in a nonspecular plane common to both surfaces is simultaneously measured, and defects in the adjacent surface areas are revealed by variations in intensity of the measured reflections. The apparatus employed generally includes a first optical system arranged to project a limited beam of light nearly tangent to the exposed end and face areas of a core end; a second optical system to collect reflected light from these areas; a pair of photodetectors;

and a mask over the detectors which has an aperture so shaped to accentuate light variations caused by defects in the surfaces by attenuating background light. Means are provided to support and rotate the package and core about the cylindrical axis of the core. Electronic circuitry is provided to amplify photodetector signals, compare them with set limits, and read out occurrence of a defect with magnitude sufficient to dictate rejection of the yarn package.

Brief description of drawings FIGURE 1 is an elevational view in section showing the optical systems;

FIG. 2 is a diagram showing the spacial relations of the optical axis and core end;

SIG. 3 is a face view of the mask and photodetectors; an

FIG. 4 is a block diagram of the associated electronic system.

Detailed description of the preferred embodiment Turning first to FIG. 1, the structure of the electrooptical part of this invention is seen to comprise first a light-tight enclosure 10 containing a first optical system 12 for projecting a beam of light and a second optical system 14 for collecting reflected light. Enclosure 10 consists of solid flat horizontal top and bottom sections 16, 18; a solid vertical rear section 20; and a complex front section comprising three flat surfaces 22, 24, 26 arranged at preselected angles as described below. Two solid end sections (not shown) are provided to complete the enclosure. Section 22 slopes upward and inward toward the back at an angle of approximately to the horizontal and extends approximately of the height of the enclosure. Side 24 extends outward and upward at to side 22. Section 26 is vertical and closes the front of housing 10. Windows 28 and 30 are provided respectively in sections 24 and 22 and arranged to transmit the incident beam of light from the first optical system and receive the reflected beam of light for the second optical system respectively. A package mounting means (not shown) is constructed and arranged to position a yarn package 32 and core 34 such that the longitudinal axis 36 of the core is horizontal and such that the core and package are rotated about this horizontal axis. Thus, this mounting presents the uncovered peripheral surface 38 and annular end surface 40 to the optical systems.

The first optical system 12 is seen to comprise a lamp 42, with filament 44, mounted by means of lamp mounting 46 on the upper part of rear surface 20 of housing 10, and energized over cable 48. A photodetector 50 is provided in the beam from lamp 42 in order to furnish a feedback signal to circuitry (not shown) designed to regu late the intensity of light from lamp 42. A double convex lens 52 is mounted by means of adjustable mounting 54 in order to focus light from lamp 42 toward a plain mirror 56. A mounting 58 is affixed to end section 26 in order to adjustably position mirror 56 so that light is projected out through window 28 and onto end and peripheral surface areas 40, 38 of core 34. The second optical system 14 is seen to comprise a lens 60 mounted in a barrel 62 by means of an adjustable support 64 and arranged to collect reflected light from surface areas 38, 40 and project it toward a mirror 66 mounted on face 18 by means of adjustable mounting 68. Mirror 66 is arranged to project the light it receives up toward a photodetector 70 supported by means of an adjustable mount 72. An apertured mask 74 is mounted in front of detector 70.

The spacial relationships between the two optic axes 76, 78 of the two optical systems, the axis of rotation 36 of the core and the two surfaces 38, 40 under inspection are best seen in FIG. 2. Here three mutually perpendicular coordinate axes are designated by lines X-X', Y-Y', and Z-Z'. If core 34 is located with its center line 36 in the XOZ' plane and parallel to the OZ axis such that its exterior peripheral surface 38 contains the axis OZ and if the optical axis 76 of the light source is coincident with the axis OY then the two surfaces 38-, 40 of the core end will be illuminated essentially tangentially as shown by a spot of light around the position 0, where the two surfaces 38, 40 meet. The optical axis 78 of lens 60 of the second optical system 14 is located in the plane OEDB which is positioned at an angle of 45 with both planes ZOY and XOY'. Axis 78 is also inclined 45 below the XOZ plane. This arrangement positions lens 60 for simultaneous viewing of reflected light from surfaces 38, 40 at a nonspecular angle common to both surfaces.

The arrangement of the photodetector 70 and its associated mask 74 is best seen by reference to FIG. 3. Mask 74 is shown partially broken away to disclose that the detector 70 comprises two photovoltaic cells 70a and 70b arranged side-by-side. Mask 74 comprises an opaque plate having a substantially rectangular slit 80 extending across the two detectors 70a, 70b. Slit 80 has, in addition, two triangular openings, 82, 84, extending from the rectangular slit and located side-by-side near the center of the slit. Opening 82 uncovers part of cell 70b, and opening 84 uncovers part of cell 70a. The sizes and shapes of slit 80 and extra openings 82, 84 are selected empirically to provide optimum signal-to-noise ratio when the planar image of the illuminated spot on surfaces 38 and 40 (FIG. 1) is projected onto mask 74 and centered as shown in FIG. 3 by the complex planar image area AMCN. The image area AMC originates -by reflectance from the annular end surface 40 whereas the image area ANC originates from the cylindrical surface 38-. Mask opening 84 falls under illuminated area AMC and opening 82 falls under area ANC.

The electronic circuitry for collecting, analyzing, and using signals from photocells 70a, 70b may take several forms. In the preferred embodiment of this invention, signals from Cells 70a and 70b are fed over cables 90, 92, respectively, to amplifiers 94 and 96. The amplified signals are then passed over cables 98 and 100, respectively, to discriminator units 102 and 104. The outputs from these discriminator units are passed through diodes 106 and 108 and then connected together through a single cable 110 and passed as a combined input to a memory device 112 which in this case takes the form of a simple shift register. This memory 112 is connected to an interrogator 114 through interrogating line 116 and furnishes output back through the interrogator over line 118 and thence over line 122 to a segregating device 120.

In operation of this invention, lamp 42 is energized over cable 48 from a power source not shown and the intensity maintained constant by means of a feed-back signal from photocell 50 in a conventional manner. Light is focused by lens 52 and directed by mirror 56 to illuminate adjacent areas of the two surfaces 38 and 40 of rotating core 34. Light reflected from surfaces 38, 40 is gathered by lens 60 at a constant nonspecular angle and directed by mirror 66 as a planar image onto mask 74 and thence on photodetector 70. Outputs from each of the two cells 70a, 70b are amplified by amplifiers 94, 96, rectified and presented to discriminators 102, 104, whereby any pulses greater than a preselected level are passed through diodes 106, 108 to memory 112. Any signal from either of the two photocells greater than a reference level will set the first bit in the shift register of memory 112. These pulses are caused by each nick or protrusion, in the surfaces 38 or 40, which is of sufi'icient magnitude to be a potential yarn-snagging point on the end of core 34. At a programmed time later when the package has reached the location of the segregating device 120, interrogator 114 interrogates memory 112 and if the shift register has been set, a segregating signal is passed to segregating device 120 which serves to place the package in the reject category.

Thus, there is provided by this invention a non-contacting inspection device which scans both the peripheral surface and the annular end surface of the protruding portion of a yarn package core of cylindrical shape, detects any defect which might cause a yarn snag when yarn is drawn off the package over this end of the core, and signals occurrences of defects so that a package with a defective core can be segregated.

It is desirable to provide multiple mountings for yarn packages which are fixed to an indexing conveyor mechanism so that multiple yarn packages can be brought to the inspection device and continuously, step-wise carried away to the segregating device located at the end of the conveyor. In operation the packages are loaded onto the conveyor, indexed to the inspection device, and then indexed to the segregating device where they are segregated according to whether or not defect signals have been stored in the memory. In this way other inspection devices than that of this invention can be placed along the conveyor and results from various tests employed to operate the segregating device. A conveyor system is not shown since it may be any one of many conventional types.

Adaptions and modifications will occur to those skilled in the art which may be made without departing from the spirit of the present invention, which is, therefore, intended to be limited only by the scope of the appended claims.

What is claimed is:

1. An apparatus for simultaneously detecting defects in adjacent areas of contiguous end and peripheral surfaces of a yarn package support, said apparatus comprising:

(a) a light source mounted adjacent one end of the support;

(b) a first optical system positioned between said light source and said support for focusing said light source substantially tangent to a point where the surfaces meet to simultaneously reflect the beam of light from adjacent areas of the surfaces;

(c) a second optical system positioned adjacent said one end for viewing and forming a planar image of the reflected light from said adjacent areas;

(d) a photodetector positioned in the image plane, said photodetector including two photocells in side by side spaced relationship;

(e) an opaque mask positioned between said optical system and said photodetector, said mask having two spaced openings, each opening being in alignment with a photocell to selectively admit imaged reflected light from the end or peripheral surface to a corresponding photocell; and

(f) means connected to each photocell for indicating variations in the amount of light reaching each photocell.

2. The apparatus of claim 1 wherein is provided means for rotating said support about its longitudinal axis.

References Cited UNITED STATES PATENTS 2,947,212 8/1960 Woods. 3,026,415 3/1962 Lake et al. 3,349,906 10/ 1967 Calhoun et al. 3,355,980 12/1967 Mathias.

RALPH G. NILSON, Primary Examiner C. M. LEEDOM, Assistant Examiner US. Cl. X.R. 250-237 

